The ultimate of all AI's aligned against you I dont think Ive done yet (though I could whip one out quick enough, maybe later today).
For now there there are random alliance maps you can get
HERE. Pick the one named for the race you want to play it fills in random opponents with random alliances to each other. They are re-rolled every day.
Or in that same place is "Poke in the Eye" which adds random alliances amoung the AI's and random monsters to every province. It makes for a very different game but actually tends to handicap the AIs more than it does the human players.
Also there, if you have the excellent Miirunst map then downloading MiirunstX.map will add scattered monsters which make it a different play.
Some that Im still messing with can be found in the
PROJECTS directory. The Indeps.zip makes Man a nation with no pretender uniting the independent provinces against everyone. Not too hard, just a fun change. The WEvsTHEM (grab the .map and the .tga) is an effort at making a game too hard to win alone. It unites Rlyeh, Atlantis, and Ermor down in one corner given them extra castles. Its a long game and supposed to make it so that human players have to ally to win (still in testing). And the latest is Mazes and Monsters (grab the MazeMons map and tga files) which is designed to add more strategic play to a game by providng more choke-points, random castles scattered around, and monsters with equipment.